superconductor

It looks more like a charcoal briquette than anything, but the black brittle thing at the bottom of [Ben Krasnow]’s crucible is actually a superconducting ceramic that can levitate magnets when it’s sitting in liquid nitrogen. And with [Ben]’s help, you can make some too.

Superconductors that can work at the relatively high temperature of liquid nitrogen instead of ultracold liquid helium are pretty easy to come by commercially, so if you’re looking to just float a few magnets, it would be a lot easier to just hit eBay. But getting there is half the fun, and from the look of the energetic reaction in the video below, [Ben] had some fun with this. The superconductor in question here is a mix of yttrium, barium, and copper oxide that goes by the merciful acronym YBCO.

The easy way to make YBCO involves multiple rounds of pulverizing yttrium oxide, barium chloride carbonate, and copper oxide together and heating them in a furnace. That works, sort of, but [Ben] wanted more, so he performed a pyrophoric reaction instead. By boiling down an aqueous solution of the three components, a thick sludge results that eventually self-ignites in a spectacular way. The YBCO residue is cooked in a kiln with oxygen blowing over it, and the resulting puck has all the magical properties of superconductors. There’s a lot of detail in the video, and the experiments [Ben] does with his YBCO are pretty fascinating too.

Superconducting wire has been around for decades now. Typically it is a thick wire made up of strands of titanium and niobium encased in copper. Used sections of this wire show up on the open market from time to time. [Patrick] got ahold of some, and with his buddies at the waterjet channel, they cut it into slices. It was then over to the lathe to shape the ring.

Once the basic shape was created, [Patrick] placed the ring in ferric chloride solution — yes the same stuff we use to etch PC boards. The ferric chloride etched away just a bit of the copper, making the titanium niobium sections stand out. A trip through the rock tumbler put the final finish on the ring. [Patrick] left the ring in bare metal, though we would probably add an epoxy or similar coating to keep the copper from oxidizing.

[Patrick] is selling these rings on his website, though at $700 each, they’re not cheap. Time to hit up the auction sites and find some superconducting wire sections of our own!